1. Field of the Invention
The present invention relates to the enzymatic resolution of lactams. The method of the present invention is useful in preparing compounds which may have utility as pharmaceutical, agricultural and veterinary products or starting materials and intermediates for their synthesis.
2. Discussion of the Prior Art
It is known in the art that chiral resolution of compounds can be achieved by using enzymes. Chiral resolution using enzymes such as esterases on aliphatic esters and cyclic compounds containing esters are described in, for example, W. Boland et al., Synthesis, 1049-1072, 1991. Chiral resolutions using enzymes in aliphatic methyl esters hydrolysis is described in, for example, H. Ohta et al., Chem. Lett.,657-660, 1992. Chiral resolutions using enzymes in cyclohexanes systems are described in, inter alia, M. Ohno, Tet. Lett., 29, 6961-6964, 1988; H. Hemmerle, Tet Lett., 28, 3471-3474, 1987; and B. Brion, Tet Lett., 33, 4889-4892, 1992. Chiral resolutions using lipases or Acetylcholine esterases on cycloheptanes containing diacetates is found in A. J. Pearson et al., JOC, 54, 3882, 1989. Beta-lactams have been reported to be selectively acylated by lipase at the nitrogen function (C. Sih et al., JOC, 58, 1068, 1993).
However, there is no prior art for the enzymatic resolution of lactam esters. It is often desired to obtain a single enantiomer of a racemic lactam ester. These compounds can be used as intermediates for preparing compounds which have utility as starting materials and intermediates for the synthesis of pharmaceutical, agricultural and veterinary products. For example, the enanantiomerically pure form of 7-carbomethoxycaprolactam is a useful intermediate in the synthesis of pharmaceutical drug candidates.